Synthesis,Photothermal Effect And Cytotoxicity Of Fe₃O₄@Au Nanocomposites

It is currently a very active research area to develop multifunctional nanocomposites（NCs）which integrate the novel properties from various nanomaterials for multimodal imaging and simultaneous therapy.These theranostic nanoplatforms can provide complementary information from each imaging modality for accurate diagnosis and,at the same time,afford an imaging-guided focused tumor therapy.This study developed a layer-by-layer assembling approach to synthesize Fe₃O₄@Au NCs with high photothermal conversion efficiency.The as-synthesized NCs showed significant photothermal ablation capability to HeLa cells in vitro under near infrared laser irradiation.To ensure the safety for medical applications,the bio-effects of Fe₃O₄@Au NCs on RAW264.7 cells were carefully assessed,in terms of cell viability,oxidative stress and apoptosis.We have demonstrated that Fe₃O₄@Au NCs had good biocompatibility in RAW264.7 cells and no significant cytotoxicity was found.Therefore,the Fe₃O₄@Au NCs synthesized in this study have great potential as an ideal candidate for CT/MR imaging and photothermal therapy.This paper is divided into two parts.The first part is the synthesis of Fe₃O₄ NPs with uniform morphology and strong surface adsorption.Fe₃O₄ NPs is synthesized by the kernel.The second part is mainly to evaluate biological effect of Fe3O4@Au to RAW264.7 cells,tem observation of nanomaterials in intracellular localization,tested the cell survival rate,the levels of oxidative stress and cell apoptosis,the detection of LDH,the photothermal ablation capability to HeLa cells.Results are as follows:（1）Fe₃O₄ NPs is the shape rule,the square of the uniform size;The presence of amino on the surface of the material helps to enhance the adsorption capacity,which can be further modified on the surface of the material.（2）The synthesized Fe₃O₄@Au NCs nano-composite material contains 83.7+3.1%Fe₃O₄ and 12.3+0.3%Au;Fe₃O₄@Au NCs is more efficient than Fe₃O₄ NPs nanoparticles.（3）Cell survival,apoptosis rate,LDH enzyme activity,ROS level,GSH enzyme activity and SOD activity all confirmed the excellent biocompatibility of Fe₃O₄@Au NCs on RAW264.7 cells.（4）Fe₃O₄@Au NCs has a good photothermal ablation effect on Hela cells.